A: When the motor shaft is machined/modified, some impact may be felt by the ball bearings within the motor. Too much impact could damage the ball bearings. Therefore, machining is not recommended. On a similar note, do not disassemble the motor. Disassembling the motor will not only dramatically lower performance, it can also cause it to cease functioning if foreign matters get inside the motor. Also, the warranty is voided if any modification is done to our products. If you would like to request any custom modifications to our products, please let us know.